This article focuses on the term "T[]ngri Qaghan" used to refer to T'ang T'ai-tzung 唐太宗. First we look at the particular instances in which this term was used to refer to the emperor. Next, we discuss the types of people to whom the honorific title "T[]ngri Qaghan" was applied. Finally, we examine the meaning and significance of the term as applied to the T'ang dynasty emperor.